powerpc/mm/radix: Avoid flushing the PWC on every flush_tlb_range

BugLink: http://bugs.launchpad.net/bugs/1709220
We do that because it's used by THP pmd collapsing, so use
instead a dedicated flush function.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
(cherry picked from commit 424de9c6e3f89399fc11afc1f53f89c5329132da linux-next)
Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/arch/powerpc/include/asm/book3s/64/tlbflush-radix.h b/arch/powerpc/include/asm/book3s/64/tlbflush-radix.h
index 7196999cdc8292310e2ef941bdc46855df75a77b..9b433a624bf3620d46cd97e6b8e563abce691169 100644 (file)
--- a/arch/powerpc/include/asm/book3s/64/tlbflush-radix.h
+++ b/arch/powerpc/include/asm/book3s/64/tlbflush-radix.h
@@ -36,6 +36,7 @@ extern void radix__flush_tlb_page_psize(struct mm_struct *mm, unsigned long vmad
 #define radix__flush_tlb_page_psize(mm,addr,p) radix__local_flush_tlb_page_psize(mm,addr,p)
 #endif
 extern void radix__flush_tlb_pwc(struct mmu_gather *tlb, unsigned long addr);
+extern void radix__flush_tlb_collapsed_pmd(struct mm_struct *mm, unsigned long addr);
 extern void radix__flush_tlb_lpid_va(unsigned long lpid, unsigned long gpa,
                                     unsigned long page_size);
 extern void radix__flush_tlb_lpid(unsigned long lpid);

diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index 01c94f141164ae561de0603cd71eb6b7c20594e1..74d50da39460e5078168f0bc4d1d9e92abee44d2 100644 (file)
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -706,9 +706,12 @@ pmd_t radix__pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long addre
         */
        pmd = *pmdp;
        pmd_clear(pmdp);
+
        /*FIXME!!  Verify whether we need this kick below */
        kick_all_cpus_sync();
-       flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+
+       radix__flush_tlb_collapsed_pmd(vma->vm_mm, address);
+
        return pmd;
 }
 

diff --git a/arch/powerpc/mm/tlb-radix.c b/arch/powerpc/mm/tlb-radix.c
index a11c3eab4ad9f515b7f9988a50eef3b559e94573..da1b5112e8c56a555e5a0610687b0088ce5f2578 100644 (file)
--- a/arch/powerpc/mm/tlb-radix.c
+++ b/arch/powerpc/mm/tlb-radix.c
@@ -280,11 +280,7 @@ void radix__flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 {
        struct mm_struct *mm = vma->vm_mm;
 
-       /*
-        * This is currently used when collapsing THPs so we need to
-        * flush the PWC. We should fix this.
-        */
-       radix__flush_all_mm(mm);
+       radix__flush_tlb_mm(mm);
 }
 EXPORT_SYMBOL(radix__flush_tlb_range);
 
@@ -369,6 +365,43 @@ err_out:
        preempt_enable();
 }
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+void radix__flush_tlb_collapsed_pmd(struct mm_struct *mm, unsigned long addr)
+{
+       int local = mm_is_thread_local(mm);
+       unsigned long ap = mmu_get_ap(mmu_virtual_psize);
+       unsigned long pid, end;
+
+
+       pid = mm ? mm->context.id : 0;
+       if (unlikely(pid == MMU_NO_CONTEXT))
+               goto no_context;
+
+       /* 4k page size, just blow the world */
+       if (PAGE_SIZE == 0x1000) {
+               radix__flush_all_mm(mm);
+               return;
+       }
+
+       /* Otherwise first do the PWC */
+       if (local)
+               _tlbiel_pid(pid, RIC_FLUSH_PWC);
+       else
+               _tlbie_pid(pid, RIC_FLUSH_PWC);
+
+       /* Then iterate the pages */
+       end = addr + HPAGE_PMD_SIZE;
+       for (; addr < end; addr += PAGE_SIZE) {
+               if (local)
+                       _tlbiel_va(addr, pid, ap, RIC_FLUSH_TLB);
+               else
+                       _tlbie_va(addr, pid, ap, RIC_FLUSH_TLB);
+       }
+no_context:
+       preempt_enable();
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
 void radix__flush_tlb_lpid_va(unsigned long lpid, unsigned long gpa,
                              unsigned long page_size)
 {